The present invention relates to a suspension conveyance system used, for example, to support car bodies in factories manufacturing automobiles or to support and carry objects to be worked in various factories.
As for suspension conveyance systems of this type, there has heretofore been provided an arrangement found, for example, in Japanese Kokai (unexamined) Publication No. 6-156662. In this conventional arrangement, the main body frame of an overhead hanger carried on a given line is provided with receiving elements on the front and rear sides, respectively, for supporting a car body. Of both receiving elements, the one on the front side is fixed and the other, which forms a pair on the rear side, are respectively rotatably supported with respect to the main body frame side.
That is, a receiving-element support member is fixed on the main body frame side. This receiving-element support member has a shaft fitted therein, which shaft is rotatable and axially movable. The shaft has an eccentric position of the receiving element fixed at the upper end thereof and a rotary piece fixed at the lower end thereof In addition, the rotary piece is formed with a pair of driving holes which are symmetrically disposed, while the receiving-element support member is provided with a position holder.
Disposed at predetermined places in the line are front end pressing means, intermediate pressing means, and rear end pressing means, which are operable with respect to the main body frame side. Also disposed is an automatic switching device consisting of a releasing means and a rotating means.
With such a conventional arrangement, the overhead hanger is carried on the line and is brought to a stop with the receiving elements, now empty, on the rear side opposed to the automatic switching device. First, swing prevention of this main body frame side is effected by causing the front end pressing means, intermediate pressing means and rear end pressing means to act on the main body frame side. Then, the releasing means in the automatic switching device is lifted, and with its driving pin fitted in the driving hole, the receiving elements are lifted through the rotary piece and shaft so as to bring the positioning effected by the position holder in an open state. In this state, the receiving elements are rotated by the operation of the rotating means through the driving pin, rotary piece, shaft and the like. Thereafter, the receiving element side is lowered for the position holder to effect positioning. In this manner, the attitude of the receiving elements on the rear side is changed by the automatic switching device.
According to the conventional arrangement described above, however, since the automatic switching device is arranged to change the attitude of the corresponding rear side receiving elements by operating the pair of releasing means and rotating means, there have been such problems that the arrangements and operations become complicated.
Accordingly, an object of the invention is to provide a suspension conveyance system capable of changing support positions of right and left supports by a common changing means.
To achieve the object described above, a suspension conveyance system according to the invention comprises a movable body movable on a given path, the movable body having a support section for an object to be carried, and supports for supporting the object from below which are disposed in a lower portion of the support section on right and left sides of the support section such that a support position can be changed, wherein the given path includes therein a changing means disposed between the right and left supports to change the support position provided by the supports.
According to the above arrangement of the invention, the movable body is moved until it is stopped with the support section, now empty, opposed to the changing means, and then the changing means is activated, thereby changing the support position provided by the support members. Thus, a plurality of kinds of objects to be carried can each be supported in a stable manner. The use of the common (single) changing means simplifies the construction and operation and ensures that the change of the support position provided by the right and left support members is effected quickly and reliably.
In a first embodiment of a suspension conveyance system according to the invention, the changing means is movable between an operating position in the given path and a retreat position outside the given path.
According to this first embodiment, the changing means performs the operation of changing the support position provided by the support members in an operating position, but when not performing such operation, it is moved to the retreat position, whereby the maintenance, inspection, repair and the like, of the changing means can be effected without stopping the movement of the movable body on the given path and without involving any trouble.
In a second embodiment of a suspension conveyance system according to the invention, there is a positioning means for positioning the support members when the movable body is stopped at a position where it is opposed to the changing means in the given path.
Therefore, according to the second embodiment, the support position provided by the supports can be changed quickly and reliably by the changing means with respect to the support section which has effected positioning (swing prevention) by the positioning means after the movable body has been stopped.
In a third embodiment of a suspension conveyance system according to the invention, there are stock sections for the support section below the given path, so that the changing means effects the switching of the support members between the support section and the stock section.
Therefore, according to the third embodiment, the common (single) changing means effects the changing of the support position provided by the right and left support members and the switching of a plurality of kinds of supports between the support section and the stock sections, thus making it possible to cope with a variety of objects to be carried.
Further, in a fourth embodiment of a suspension conveyance system according to the invention, the supports have removable attaching pins to be inserted into the support section from above and support pins capable of having an object to be carried fitted thereon from above. These attaching pins and support pins are transversely spaced from each other.
Therefore, according to the fourth embodiment, when the object to be carried is unloaded from the support section by upwardly disengaging it from the support pins, the frictional resistance in the fitting region between the support pins and the object to be carried produces a force which tends to lift the supports to extract the attaching pins from the support section so as to disengage the supports. At this time, since the attaching pins and the support pins are transversely spaced from each other, the lifting direction of the supports during disengagement of the object to be carried becomes an arcuate direction with the center thereof located at the attaching pin, thus increasing the frictional resistance in the attaching pin. As a result, the disengagement of the supports can be automatically prevented.